Those were the two things I learned today.I was coding a project during exams I proctored. I had trouble finding the source to a problem. Late in the afternoon I identified the problem to be bad soldering job by a student of mine. So never trust a student fully. They have to earn the trust. Don't design a circuit so that when it is assembled, the LCD blocks access to the bottom of the MCU (impossible to fix the loose solder job).

Since the LCD was in the way, I wasn't able to apply solder to the loose pin. I jammed a length of wire in that socket pin and soldered the other end of the wire to a via, which is supposed to go to that pin on the PCB. So don't try to be perfect when designing PCBs and leave no/few vias around, you will be sorry you can't fix stuff by soldering wires to the vias. XD XD XD

I rarely make mistakes - but I've had 2 happen in my 2 years of designing in here. I had one board that underwent a late parts move; 4 wires ripped up to make room and never re-connected, another with 1 letter missing from name - so 2 pins ended up with +5 instead of +5V.A 2nd board I converted from DIP to TQFP - 1 output signal attached to the new symbol got connected to A6 instead, which is analog input only.Both easy to get working with wires added where traces were missing.Everything I've offered up to the group for purchase has been error free.

Well I was once a student, so I of course know better then to ever trust one, ever!

As for being perfect in my projects, I take a different approach. I know I'm going to design/build in mistakes so I only build hardware stage by stage and test each stage before proceeding on to the next. I take a similar approach with my programs, rather then write the complete thing I write function by function, testing each with a simple main loop and when I have all the functions working the way I think it should, I just write the main loop to stitch all the functions together. Works for me and I have fun along the way rather then just building everything first and having a big disappointment at the end and trying to figure out what stage or function might be causing the symptom or error(s).

I Never trust a student... Generally it was me that did the critical training... And PC boards are Always... A Work in Progress.Occasionally one of my customers complains when I say that and my standard retort is... "I wasn't aware perfection was a part of our contract... I only guarantee it to work as we agreed and WE never discussed "Perfect""In 20+ years of making PCB's... If the first article works W/O modification and the board house didn't complain too loudly... about making it...I have reached the NECESSARY level of Perfection. You can spend HOURS seeing to every vertice being exactly on grid, that the wire spacing is a perfect parallax illusionand in the end the board has no shame whatsoever.... It still works more or less as the design did... It is when the PCB whose connectivity is IDENTICAL (as checked by 3 people) and is identical in connectivity with schematic and breadboard and still refuses to work...That I get worried.

Bob

--> WA7EMS "The solution of every problem is another problem." -Johann Wolfgang von GoetheI do answer technical questions PM'd to me with whatever is in my clipboard

Occasionally one of my customers complains when I say that and my standard retort is... "I wasn't aware perfection was a part of our contract... I only guarantee it to work as we agreed and WE never discussed "Perfect""

That is a answer I need to remember.Thanks for sharingBest regardsJantje

Do not PM me a question unless you are prepared to pay for consultancy.Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -

Occasionally one of my customers complains when I say that and my standard retort is... "I wasn't aware perfection was a part of our contract... I only guarantee it to work as we agreed and WE never discussed "Perfect""